A small lightweight alarm can serve as a perimeter tripwire alarm, as a signaling device in both light and dark, as a flashlight and as a personal security alarm. One or more of the alarm units can be used to enclose and secure a small or large perimeter, such as a road, a path, a campground or a tactical position. An audible alarm can be activated manually on demand as a personal security alarm by operating a switch or unintentionally by an intruder by engaging a tripwire.
In one embodiment a loud chirping alarm is accompanied by a flashing or strobing light, while in another embodiment a loud chirping alarm is accompanied by strobing infrared light. In each embodiment, the alarm including both audible and visual alarm components is activated by removing a pull pin from the body of the alarm. The flashing or strobing light can be activated without an audible alarm with a separate user-actuated switch.
To set up the alarm as a perimeter tripwire alarm, a compact alarm base unit is secured in place in any convenient manner. The base unit can be provided with a kit which includes a strip of adhesive tape, such as black duct tape having a peel-off backing, several meters or more of monofilament trip line, one or more compact wafer-shaped light assemblies and one or more nylon zip ties or “tie wraps.”
The base unit can be provided with an adhesive backing having a peel-off cover. The base unit can be adhesively mounted on almost any surface, such as a clean flat glass, plastic, wood or metal surface, with an adhesive provided on the back of the base unit, such as a double sided foamed adhesive tape. The adhesive can be exposed by peeling off its protective cover. The base unit can then be adhesively fixed in position by simple manual pressure of the adhesive backing against virtually any substrate.
Alternatively, adhesive tape, tie wraps, rope, bungee cords or other fasteners can be used to secure the base unit in place. Even trees, logs, cut branches, rocks and the like can be used as a substrate to secure the base unit in position on the perimeter of a secured area.
Once the base unit is secured in position, a monofilament trip line is tied to the pull pin. The pull pin is inserted in an alarm switch and stretched across a trail, path, road, open area or any other desired perimeter or location to be secured. The other free end or “bitter end” of the trip line is secured to a fixed object at the next position on the perimeter. A simple knot in the trip line can be used to fix the free end of the trip line to any suitable anchor point. Alternatively, a compact light assembly as described below can be used for this purpose if a somewhat flat surface is available. One or more separate compact light assemblies can be provided in a kit along with the base unit, trip line, tape and ties.
The compact light assembly or light assemblies provided in the kit have an adhesive backing with a peel-off cover allowing a compact light assembly to be adhesively mounted to virtually any surface which is preferably clean and dry. Alternatively, the compact light assembly can be mounted on the base unit and illuminated with a simple manual push on a three way pressure switch. A first press illuminates a fast strobing light which in one embodiment is a blue LED light. A second press illuminates a slow strobing light, a third press illuminates a constant light and fourth press turns the constant light off and resets the compact light assembly to operate again in the same series of operating modes noted above.
The base unit can further include one or more lights operated by an on-off switch, such as a manual sliding switch. In one embodiment, a red LED light is provided on the base unit serving as a flashlight for reading maps in the dark, viewing other objects in the dark or signaling in the light or dark. One or more blue LED lights can also be provided on the base unit for signaling or for identifying blood stains, such as when tracking a wounded animal The blue lights can be activated by a strobing circuit to provide a strobe light effect. The manual sliding on-off switch can select a strobing mode on the blue lights. Removing the pull pin will also activate the strobing mode on the blue lights, as well as the audible alarm to provide an effective personal security alarm or alternatively, a trip wire perimeter alarm providing both audible and visual alarm signals.
In one embodiment, the blue light is strobed and directed into a clear plastic light pipe for light transmission and concentration. The light pipe can include grooved or prism-shaped internal surfaces which efficiently direct light away from the base unit in a predetermined direction or directions.
In another embodiment, the blue light is replaced with an infrared light, such as an infrared light emitting diode (LED), which can be provided with a strobing function. This infrared light can be used in conjunction with night vision infrared viewing apparatus, such as used in military and tactical operations. The infrared light allows for the detection of the position of the base unit at night without alerting others without the aid of night vision viewing equipment.